Patent GB-1068799-A (GB)
Title: Stoving lacquers
Inventor: LOUIS GERD
IPC: C09D133/26
Filed: 1965-10-01
Abstract: Stoving lacquers, particularly suitable for application to metals, contain at least one organic solvent and at least one copolymer consisting of units of (a) 10 to 40 parts by weight of an alkyl ether of N-hydroxymethyl-acrylamide or -methacrylamide, or a mixture of two or more such ethers; (b) 10 to 75 parts by weight of an alkyl ester of acrylic or methacrylic acid, or a mixture of two or more such esters; (c) 1 to 10 parts by weight of acrylic, methacrylic or maleic acid, or a mixture of two or more such acids; and (d) 1 to 50 parts by weight of at least one other ethylenically unsaturated compound consisting to the extent of 1 to 15 parts by weight of at least one cycloaliphatic hydroxyhydrocarbon containing (i) the nucleus of bicyclo-[2,2,1]-heptene-(2), (ii) 1 to 3 hydroxy groups and (iii) 7 to 17 carbon atoms.  Suitable solvents include aromatic hydrocarbons and aliphatic ketones, alcohols, esters, ethers and ether-esters and mixtures thereof.  As the hydroxy-bicycloheptene component of the copolymer, the 5-hydroxy, 5-hydroxymethyl, 5-hydroxyethyl, 5-dihydroxyethyl and 5,6-bis-(hydroxymethyl) derivatives are specified.  Units (d) of the copolymer may also comprise those derived from monomers such as acrylonitrile, styrene and monoesters of acrylic or methacrylic acid with alkanediols containing 2 to 6 carbon atoms.  The lacquers may optionally include aminoplast (e.g. melamine - formaldehyde precondensate), phenoplast, epoxide or alkyd resins, pigments (e.g. titanium dioxide), soluble dyes, cure catalysts and flow improvers.  In examples the basic lacquers (i.e. organic solvent/copolymer solutions) are prepared by polymerizing the appropriate monomers in an n-butanol/xylene mixture in the presence of t-dodecyl mercaptan and using azodi-isobutyronitrile as initiator, the latter being added portionwise during polymerization.ALSO:Stoving laquers particularly suitable for application to metals, e.g. iron, aluminium, magnesium and alloys thereof, contain at least one organic solvent and at least one copolymer consisting of units of (a) at least one alkyl ether of N-hydroxymethyl-acrylamide or -methacrylamide (b) at least one alkyl ester of acrylic or methacrylic acid (c) at least one of acrylic, methacrylic and maleic acid and (d) at least one other ethylenically unsaturated compound, part or all of which is at least one bicyclo- [2,2,1]-heptene-(2) derivative containing 1 to 3 hydroxyl groups and 7 to 17 carbon atoms.  Optional units (d) may be, for example, those derived from acrylonitrile, styrene or monoesters of acrylic or methacrylic acid with alkanediols containing 2 to 6 carbon atoms.  Suitable solvents include aromatic hydrocarbons and aliphatic ketones, alcohols, esters, ethers and ether-esters and mixtures thereof, e.g. n-butanol/xylene.  The lacquers may optionally include aminoplast (e.g. melamine-formaldehyde precondensate), phenoplast, epoxide or alkyd resins, pigments (e.g. titanium dioxide), soluble dyes, cure catalysts and flow improvers.  The lacquers may be applied by conventional methods and stoved at 120-180 DEG C. for periods ranging from 10 minutes to 2 hours.  Examples illustrate the production of lacquerings on deep drawing iron sheets.